Optical image defocus correction

In an optical/electrical imaging system, optical depth of focus corrections are accomplished electronically. A plurality of defocus states of the optical system are measured and/or determined and image restoration coefficients corresponding to each of these states are stored. The state of defocus of the imaging system is then determined by deriving an image from a target having known characteristics, which are then correlated to determine a state of defocus. A microprocessor is utilized to provide appropriate defocus correction information to an electronic filter, thereby providing an adaptive filtering arrangement.